#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

int missingNumber(int* nums, int numsSize)
{
	int n = numsSize;
	int ret = (n + 0) * (n + 1) / 2;
	
	for (int i = 0; i < numsSize; ++i)
	{
		ret -= nums[i];
	}

	return ret;
}

int main()
{

	return 0;
}